Solvent extraction is a method for separating a compound or substance from one or more other compounds or substances by using one or more solvents. This method is used in industry, and in the laboratory for refining, isolating and purifying a variety of compounds such as oil from seeds. In liquid-liquid extraction, the compound to be extracted is dissolved in a liquid and a liquid solvent is used for the extraction. The process relies on variations in the solubilities of different compounds in different substances. The method may also be applied to solid materials that contain compounds that need to be extracted. Generally, the solvent used dissolves the compound leaving behind the solid material that contained it.